Valve-gear for piston-engines.



E. SCHMID.

VALVE GEAR FOR PISTON ENGINES.

APPLICATION FILED MAY 22. I9I4. 1,213,274. Patented Jan.23,1917.

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mmm/WIM @IMM E. SCHMID. VALVE GEAR FOR PISTON ENGINES.

APPLICATION FILED MAY 22. I9I4. 1,213,274. Patented Jan.23,1917.

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ERNST SCHMID, 0F OERLIKON, SWITZERLAND.

VALVE-GEAR FOR PISTON-ENGINES.

Specification of Letters Patent.

Patented Jan. 23, 1917.

Application led May 22, 1914. Serial No. 840,221.

T 0 all whom it may concern Be it known that I, ERNST SoHMiD, a citizenof the Republic of Switzerland, residing at Oerlikon, Switzerland, haveinvented new and useful Improvements in Valve- Gears for Piston-Engines;and I do hereby declarethe vfollowing to be a full, clear, and exactdescription of the invention, such as will enable others skilled in theart to which it appertains to make and use the same, reference being hadto the accompanying drawings, and to let-ters or figures of referencemarked thereon, which forni al part of this specification.

The object of the present invention is to provide an eilicient packingfor valve rods and more especially valve rods of an explosion motor orair compressor and all cases where a valverod is to be packed withrespect to a cylinder head; and the invention consists in providing oneor more chambers in which the gas escaping from the cylinder duringcompression expands and is exhausted from said chambers during thesuction period by periodically connecting the chambers with the space inthecylinder for the charge of gas.

One form of carrying the invention into effect is shown by way ofexample in the accompanying drawings in which:

Figure l shows a longitudinal section of an explosion motor, the workingpiston and the valve gears being illustrated in the position which theytake-up at the beginning of the explosion period. The parts notnecessary for the understanding of the invention are omitted. Figs. 2-6show the same longitudinal section, the different parts beingillustrated in other working positions. Fig. 2 shows the parts in theposition which they take up at the beginning of the exhaust period, Fig.3 shows the parts in the position, which they take up atthe beginning ofthe admission period, Fig. 4 shows said parts in the position, whichthey take up when the admission opening is half opened and Fig. 5 showsthem in the position, which they take up when the admission opening iscompletely opened, Fig. shows the parts in Jthe position, which theytake up at the beginning of the compression period.

1 denotes the working cylinder surrounded by a cooling jacket 2.

3 denotes the working piston, 1 the piston rod, 5 the crank and 6 thecrank shaft.

7 denotes a water cooled cylinder cover 11 by means of its edges.

lprojecting into said chamber.

sion is provided all around with channels around the whole cylinder, sothat very large admission and outlet openings may be provided. Betweenthe cover 7va'nd'the working pistonfS there is' arrangedv an annularslide valve 12. The outerl diameter of this valve 12 is in the presentinstance equal to the inner diameter of the` cylinder 1. Nooutlet-passages are provided in this valve 12 and the latter controlsthe channels 10 Vand Two piston rings 13 and 14 surrounding the valveprevent a leakage of gases during the explosion and compression periods.The-lower piston ring 13 is moved at times into the position, which hadbeen previously taken up by the upper piston ring 14: of the workingpiston 3 so that it is not necessary to provide a special lubricationfor the annular slide valve 12, the required lubrication being effectedby the working piston 3. Inside the slide 12 there is provided across-piece 16 to which the stem 17 of said slide 12 is fixed. The stem17 passes through the sleeve 8 and the nut 9 and it is guided in asocket 18 disposed above the cover 7. The stem 17 has a longitudinalbore 19 extending over a part of its length. Two upper ports 2O and twolower ports 21 extend from said bore to the outer surface of the stein.rlhe latter has moreover an annular recess 22. The sleeve 8 confines aspace 23 forming an expansion chamber and it has a tubular extension 24This exten- 25, which are in communication with the cylinder 1. The nut9 and the cover of the sleeve 8 confine a space 26, which acts also asan expansion chamber.l To the stem 17 of the annular slide valve thereis operatively connected a double armed lever 28 pivotally arrangedabove the cover 7 inside the casing 27. The two ends of saidlever arepivotally connected by means of rods 29, 30 to the cranks 31, 32, whichreceive their drive from the shafts 38, 34. The shaft 311 receives itsdrive from the crank shaft 6, there being provided for this purposeeither chain wheels 35, 36 and a chain 37 or toothed wheels, the ratioof transmission being 1 :1.

@n the other hand the motion of the crank shaft G is also transmitted bymeans of the sprocket wheels 3S, 39 and the chain 40 to the shaft 83,the ratio oi.I transmission being 1:2. n

s The manner of operation of the slide valve 12 irill be evident fromthe drawings. The large size of the admission and outlet openingsprevents a backing up of the gases during the exhaust period and theformation oi" a vacuum during the suction period, notwithstanding thefact that the number of revolutions is very high. The compression andexplosion pressures are transmitted to the lower part or the stem 1T ofthe slide valve 12 and the channels 10 and l1 are arranged one nearanother, so that the slide valve 12 may be made short and very light.

The tightening of the stem 17 is accomplished in the following manner:The Working fluid, for instance gas, which during the explosion period(Fig. 1) leaks through the clearance existing between the outer surfaceof the stem 17 and the inner surface of' the tubular projection 241passes into the chamber 23, Where it will immediately eX- pand. 1t isclear, that these gases can only pass into the chamber 23 during the compression, explosion and exhaust periods.-

During the suction period the chamber 23 Will be connected by means oitthe channels 25, the ports 21, the bore 19 and the ports 20 to the spacefor the charge or the cyl' inder (Fig. 1), so that the gas which mayhave leaked into this chamber 23 Will be sucked out when new gases aresucked in the cylinder. For the purpose of facilitating the flowing backot these gases thel connection between the chamber 23 and the Workingcylinder 1 is made during the suction period. As shown in Fig. 5, thesecond expansion chamber 26 will only be opened after the expansionchamber 23 is already in communication with the space for the charge,said chamber 26 acting only as a safety chamber. The gases, Which mayhave leaked into the chamber 26, are then sucked through the annularrecess 22 into the chamber 23 and from the latter into the cylinder 1.Experience has shovvn, that even in cases, Where the stem 17 ot theslide valve 12 has a considerable play in the tubular projection 2e andin the Whole nut 9, no gas Will escape into the atmosphere. This provesthat the time interval between the end of a suction period and thebeginning of the next suction period is too short to permit theexplosion pressure to be transmitted through the chamber 28 to theatmosphere and it proves further, that the channels for the flowing backoi the gases are suliiciently large to convey the gas, Which mayeventually have leaked into the chamber 23, back into the space for thecharge during the suction period. This arrangement permits a goodtightening o the stem 17. This could not be effected if piston ringswere used, as the diameter of these rings would be so small that theywould be practically of no value. Also the packings used in stuilingboxes would not permit satisfactory results. The hereinbefore describedtightening may also be used at the place, where the gasolcne is directlyinjected into the cylinder. 1n this case the injection is also eii'ectedthrough the ports 20, the bore 19. the ports 21 and the channels 25. Asthe back-pressure acting upon the stem 1T is very small, the socket 18may be made very light. The annular slide valve 12 may -also be providedwith ports for the gas and it could also be acted upon by only oneconnecting rod. The stem oit' said valve could also be arranged at anangle to the axis oi" the cylinder. This annular slide valve may furtherbe provided in connection with every kind of valve gears and the shafts3S and 84 may also be arranged in the head of the cylinder. rllhecontent of the chamber 26 could also be sucked out during theV outletperiod. Instead oi providing in connection with the nut 9 a singlechamber 26 there could also be provided several such chambers arrangedone behind another, which would then be successively emptied into theWorking cylinder 1. There Ina-y also be provided only one expansionchamber.

W'hat I claim is:

1. In a packing for valve rods of combus tion engines, the combinationwith a valve rod projecting through the iva-ll of the eny gine cylinder,of a chamber surrounding the valve rod and adapted to receive and permitan expansion of gas escaping from the engine cylinder around the valverod, said rod having means :tor connecting periodically the chamber andcylinder, to permit the gas in the chamber to be sucked through thevalve rod from said chamber into the cylinder.

2. In a packing for valve rods of combustion engines, the combinationwith a valve rod projecting through the Wall of the engine cylinder, ofa chamber surrounding the valve rod and adapted to receive and permit anexpansion of O'as escaping from the engine cylinder around the valverod, said valve rod having means for connecting periodically the chamberwith the charge space of the cylinder to permit the gas in the chamberto be sucked through the valve rod from the chamber into the cylinder.

3. 1n a packing for valve rods of combustion engines, the combinationwith a valve rod projecting through the Wall of the engine cylinder, ofa plurality of annular eX- pansion chambers surrounding theV valve rodand adapted to receive and permit an expansion of gas escaping from theengine cylin der between the valve rod and the inner walls of thecylinder, said rod having means for connecting the chamber with thecharge space of the cylinder during the suction period to permit the gasin the chamber to be sucked through the valve rod from the chamber intothe cylinder.

4. In a packing for valve rods of a conibustion engine, the combinationwith a valve rod projecting through the wall of the engine cylinder, ofa plurality of annular expansion chambers arranged in tandem andsurrounding the valve rod and adapted to receive and permit an expansionof gas escaping from the engine cylinder between the valve rod and theinner wall of the cylinder, said rod having means for connecting thechambers with the charge space of the cylinder during the suction periodto permit the gas in the chamber to be sucked through the valve rod fromthe chamber into the cylinder. v

5. In a packing for valve rods of a combustion engine, the combinationwith the engine cylinder, of a cylinder cover, a hollow sleeve arrangedcentrally in said cover, a tubular extension in said sleeve projectinginto the hollow space of the latter, a nut screwed in the cover, anannular chamber provided between the sleeve and the nut, a valve rodpassing through said tubular eX- tension and nut and having alongitudinal hollow portion, ports leading from said hollow portion tothe surface of the rod, channels in said tubular extension connectingthe space for the charge of the engine cylinder with the hollow portionoi' the rod, and an annular recess in the valve rod for connecting thehollow sleeve space to the chamber provided between the sleeve and thenut. In testimony that I claim the foregoing as my invention, I havesigned my name in presence of two subscribing witnesses.

ERNST SCHMID. lVitnesses CARLY GUBLER, ARNOLD LEHUER.

Copies of this patent may be obtained for ve cents each, by addressingthe Commissioner of Patents. Washington, D. G.

